Pour the milk into a small saucepan and place over medium heat.
Once steaming, but not yet at a boil, remove from heat and add the tea bag. Set aside for 5 minutes, then discard the tea bag and allow the milk to cool to room temperature. If using loose leaf tea, strain before using.
Preheat oven to 350˚F (180˚C). Line 12 muffin cavities with muffin/cupcake liners or lightly grease with vegetable oil.
Place the flour, baking powder, cinnamon, baking soda, ginger, cardamom, allspice, nutmeg, cloves, salt, and black pepper in a medium bowl. Stir until evenly combined and set aside.
In the bowl of a stand mixer fitted with a paddle attachment or a large bowl with a hand mixer, beat the butter until fluffy.
Beat in the vegetable oil until completely combined, then the granulated sugar and brown sugar.
Beat in the eggs, one at a time, just until mixed in.
Beat in the vanilla extract, followed by the room temperature chai-infused milk.
Add the flour mixture, beating just until no streaks of flour remain.
Transfer the mixture among the 12 prepared liners, filling them about 2/3 full.
Bake in the preheated oven just until set and a toothpick inserted in the center comes out clean, 16-18 minutes.
Transfer the cupcakes to a wire rack and cool to room temperature.